Video: What is Mycelium? - Definition & Function

You have probably seen mycelium in your kitchen cupboard or refrigerator. Not sure what mycelium is? Read on. In this lesson, you will explore the definition of mycelium and the function and importance of these structures in nature.2016-03-01

You have probably seen mycelium in your kitchen cupboard or refrigerator. Not sure what mycelium is? Read on. In this lesson, you will explore the definition of mycelium and the function and importance of these structures in nature.

Definition

Have you ever seen the spiderweb-like structures that grow on moldy bread or a rotten tomato? These strings are often white or cream colored and grow in long fibers called hyphae. This structure, as a whole, is the vegetative structure of fungi called the mycelium. Mycelium is typically found in soils and on other organic matter.

Oyster mushroom mycelium growing on coffee grounds.

The Structure of Mycelium

To understand mycelium, you must first understand fungi. Fungi are specialized eukaryotes that can break down very complex structures in nature. They have cell walls rich in chitin (the hard material found in the exoskeleton of insects) and utilize asexual reproduction through spore release. These spores have the ability to turn into mycelium. However, a mycelium is asexual until it joins with another mycelium to form a dikaryotic mycelium. These mycelium can then create fruiting bodies, more commonly known as mushrooms.

It should be noted that fruiting bodies only occur when nutrients, gas exchange and temperature are adequate to produce them. Too much moisture or drought-like conditions are not conducive to mushroom growth.

Mycelium come in many sizes, from very tiny to as large as a forest. These mycelium are made up of rigid cell walls, allowing them to move through soil or other environments that require extra protection. Under a microscope, mycelium can look like little trees before fruiting bodies mature.

Early growth of mycelium under a microscope. Notice how it looks similar to a tree.

Function

Mycelium extend the area in which a fungi can find nutrients. Think of mycelium as extra-long fingers. If you had extra-long fingers, what could you reach without moving? Fungi are stationary organisms; however, mycelium grow outwards to look for water and nutrients such as nitrogen, carbon, potassium and phosphorus, which the mycelium transports to the fruiting body so it can continue to produce biomass and grow.

Notice the extended finger-like structures of this mycelium.

In some cases, mycelium are able to grow into a plant root cell to tap into other plant nutrient pools and exchange nutrients with the fungi and plants as needed. Think of this as a city water supply. All the houses, or in this case, plants and fungi, are strung together by pipes, which is the mycelium providing needed nutrients.

Lesson Summary

Mycelium are the vegetative structures of fungi, made up of white or cream colored long fibers called hyphae. Mycelium grow on organic matter and are asexual until joining with another mycelium. After joining, the two mycelium are capable of creating a fruiting body that produces a mushroom. Then, mycelium can continue to forage for nutrients and water to create biomass and grow. Mycelium extend the area in which a mushroom or fruiting body can acquire nutrients. Like fungi, mycelium have rigid cell walls made of chitin (a tough substance also found in exoskeletons) that allow them to grow through or into environments that would typically not allow other cell structures. Mycelium also link plants through the root system and allow them to swap nutrients in adverse climatic and growing conditions.

Summary:

Earning College Credit

Did you know… We have over 160 college
courses that prepare you to earn
credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the
first two years of college and save thousands off your degree. Anyone can earn
credit-by-exam regardless of age or education level.